This invention relates to a process for producing 3-oxo-6-formyl-2-oxabicyclo[3.3.0]-6-octene.
3-Oxo-6-formyl-2-oxabicyclo[3.3.0]-6-octene (hereinafter referred to often as aldehydelactone) is a compound useful as an intermediate for producing prostaglandins which are physiologically active substances having a number of pharmacological activities such as blood pressure depression, anti-ulceration, bronchodilation, inhibition of gastric acid secretion, partus induction, etc.
The known processes for producing this aldehydelactone comprise a large number of reaction steps. For example, L. A. Paquette et al reported a process for producing the aldehydelactone consisting of 12 to 14 reaction steps (see Tetrahedron, Vol. 37, page 281 (1981)). The process, however, is not an easy one for producing the intermediate since it comprises a number of complicated reaction steps, and especially among these steps is included an ozonolysis reaction at a low temperature of -78.degree. C.
The present inventors have conducted extensive research on a photo-addition reaction between a cis-2-cyclopenten-1,4-diol derivative and 2,2-dimethyl-1,3-dioxin-4-one, and have found that it is possible to obtain the aldehydelactone in a few steps without isolating the resulting photo-addition reaction products of cis-2-cyclopenten-1,4-diol, and thus have attained the present invention.